This invention relates to disposable medical electrodes, and a method for making the same, and more particularly to disposable electrocardiogram electrodes.
The delivering or monitoring of electrical signals to or from the human body is widespread. Hence, many types of electrodes have been developed through which electrical contact with the human body can be made. These electrodes are either permanent (i.e., reusable) electrodes, or disposable electrodes which are utilized only for a single patient and then discarded. The disposable electrodes have largely resulted from attempts to reduce the costs involved in the upkeep and cleaning of the permanent electrode between uses, as well as the patient and electrode preparation required prior to each use of the permanent electrodes. Such cost reduction attempts, however, have necessarily been tempered to ensure that the integrity and quality of the electrical contact established by the electrode was not sacrificed. Hence, most of the existing disposable medical electrodes retain metallic (silver/silver chloride) portions embedded within a packaged conductive gel to achieve integrity within the electrical contact (See, e.g., U.S. Pat. No. 3,868,946). These metallic components make up a large portion of the electrode's cost and thus substantially limit the amount by which the manufacturing cost can be reduced. The requirement of accurately placing the metallic component within the electrode also severely limits the efficient automation of the electrode manufacturing process.
Another concern with the development of disposable electrodes was the potential that the conductive gel contained therein and used to increase the electrical contact between the electrode and the human body, might eventually desiccate, or might otherwise migrate to undesirable locations on the electrode, prior to the use of the electrode, thus conceivably degrading, if not destroying, the electrode's efficacy. To prevent either of these occurrences the existing electrodes generally incorporated an integral and centralized cup-like cavity in which the conductive gel was restrained and sealed (See e.g. U.S. Pat. No. 4,126,126), and which had an adhesive coated flange-like projection extending outward from the side of the cavity to attach the electrode to the human body. To facilitate the manufacture of this central cavity and projecting flange, the existing electrodes typically had the configuration of a disk with all of the electrodes's components centrally mounted thereon. This configuration, although allowing a partially automated manufacturing process, still required substantial manual interface to critically align the various components forming the electrode.